No, once the coolant level is good you should never have to add water. However you may have to add water once or twice if there was an air pocket in the cooling system, but no more than that. If it continues, look for a leak. If you don't see a leak, have the engine checked for a blown headgasket.

...unning. When the air conditioner is off the thermostat returns to normal... I have replace the coolant, thermostat, radiator cap, radiator heat sensor, all hoses and installed a new radiator. Could...